1749838

Information

• Patent Grant
• 1749838

• References
• Source

• Patent Number

  1,749,838

• Date Filed

  Not available

• Date Issued

  Tuesday, March 11, 1930
  95 years ago

• CPC

  • H04Q5/06 - Signalling by amplitude or polarity of dc

• US Classifications

  • 379 - Telephonic communications
  • 340 - Communications: electrical